Technical Field
The present disclosure relates to metal resistors, and more specifically, to methods of forming a metal resistor with lower temperature coefficient of resistance (TCR) and low sheet resistance using ion implantation.
Related Art
Metal resistors are widely used in integrated circuit fabrication processes. For example, precision metal resistors are employed as resistors and electronic fuses (e-fuses) within integrated circuits to enable advanced functionalities that improve performance, provide memory on passive devices, provide chip identification, etc. Current metal resistor processing includes depositing a conductor on a substrate, e.g., silicon dioxide (SiO2), and annealing to stabilize the material. Current processing typically uses a tungsten silicide, WSi2.7, as the conductor. The conventional processing is disadvantageous because it creates a high temperature coefficient of resistance (TCR) and a relatively high resistivity. Temperature coefficient of resistance (TCR) describes the relative change of resistance that is associated with a given change in temperature. One approach to solve these issues is to employ other materials with lower TCR, but these materials are typically not compatible with semiconductor integration flow. For example, use of silicide WSi2.2 has been attempted, but it exhibits high non-uniformity and thus is difficult to employ.